Thread: Flattening hand plane soles (again)

Originally Posted by mic-d

What snafu is doing is nothing new. A few of us on here have been scraping planes for some time and explaining why (often with patience- sometimes not for some time).

Snafu, you won't be starting a useful argument, probably just going over the same stuff from a few years back with a new audience

And here's me thinking I was being all creative . I'd spent a good deal of time searching on the net for information about scraping plane soles, but, as always, should really have just looked here first - the post you've linked me to is fantastic. I will now go and study deeply...

Mic-D, can I ask why you've elected to scrape the entire soles, rather than the three/four contact spots that I've concerned myself with? Is there any improvement in plane performance? (Am also about to read your work on handplane mathematics...)

Originally Posted by snafuspyramid

And here's me thinking I was being all creative . I'd spent a good deal of time searching on the net for information about scraping plane soles, but, as always, should really have just looked here first - the post you've linked me to is fantastic. I will now go and study deeply...

Mic-D, can I ask why you've elected to scrape the entire soles, rather than the three/four contact spots that I've concerned myself with? Is there any improvement in plane performance? (Am also about to read your work on handplane mathematics...)

The first few pages of that post I was struggling with glass until my surface plate arrived - if you study it, study it in what not to do

I didn't elect to scrape the whole sole. When the sole is convex as many of them are, you have to scrape the whole sole. Indeed with scraping you can over-scrape the unimportant areas selectively al la Japanese plane sole shape tradition. (whether it makes a difference can't do that with lapping!) When the sole is concave I just scrape til I've got the key areas coplanar.

Originally Posted by mic-d

There are very good reasons for having a flat sole (and I don't mean an entire flat sole). Since the sole registers the blade it stands to reason that a a flat sole is the easiest way to give consistent registration. Scraped planes are super easy to use, the registration of the work to the toe is positive which helps to get started, and flat soles hav the lowest error which is practically important when jointing. If you want to know more about the geometrical reasoning behind flat soles there is this blog:
Hand plane mathematics I - Woodwork Forums (There are 5 posts)

Snafu, you won't be starting a useful argument, probably just going over the same stuff from a few years back with a new audience

Mic - having read the first two blog pages, and having asked on here before once why a hand-plane isn't stepped like a jointer(buzzer) - I think there is a flaw in the model.

Unless it is a #10 or #10-1/2, most handplanes are wider than the iron. So if you had a small blade projection and a convex blade, you might only be cutting with 10mm of the iron in the centre of the width of the plane. That plane could register on the surface being planed along its entire length, cutting only a semi-circular trench underneath part of it (and ejecting the waste upwards). The same applies even if the blade is cutting full width, convex or not. The full length of the edges of the plane can be resting on the work surface with the blade cutting away underneath it.

I haven't thought about the complication that, after the first stroke is taken and the first 'furrow' dug, then depending on the degree of overlap of the strokes then one side of the plane could be resting on a surface 1 or 2 or 4 thou lower than the other. OR 90% of the width of the plane could be resting on the 'higher' surface and one side 'flying' a thou or whatever above the last 'furrow'.

Just meant as food for thought if you're interested - don't want to derail the thread.

Cheers,
Paul

Originally Posted by pmcgee

Mic - having read the first two blog pages, and having asked on here before once why a hand-plane isn't stepped like a jointer(buzzer) - I think there is a flaw in the model.

Unless it is a #10 or #10-1/2, most handplanes are wider than the iron. So if you had a small blade projection and a convex blade, you might only be cutting with 10mm of the iron in the centre of the width of the plane. That plane could register on the surface being planed along its entire length, cutting only a semi-circular trench underneath part of it (and ejecting the waste upwards). The same applies even if the blade is cutting full width, convex or not. The full length of the edges of the plane can be resting on the work surface with the blade cutting away underneath it.

I haven't thought about the complication that, after the first stroke is taken and the first 'furrow' dug, then depending on the degree of overlap of the strokes then one side of the plane could be resting on a surface 1 or 2 or 4 thou lower than the other. OR 90% of the width of the plane could be resting on the 'higher' surface and one side 'flying' a thou or whatever above the last 'furrow'.

Just meant as food for thought if you're interested - don't want to derail the thread.

Cheers,
Paul

Nope the model is not flawed. It is based on jointing an edge, as analogous to jointing on a machine jointer. In this case the work is narrower than the blade and the model stands.

Originally Posted by mic-d

Nope the model is not flawed. It is based on jointing an edge, as analogous to jointing on a machine jointer. In this case the work is narrower than the blade and the model stands.

Ah. Touché.